void Middlepoint(CDC *pDC,int p0_x,int p0_y,int p1_x,int p1_y,COLORREF color);
void DDA(CDC *pDC,int p0_x,int p0_y,int p1_x,int p1_y,COLORREF color);
void Bresenham(CDC *pDC,int p0_x,int p0_y,int p1_x,int p1_y,COLORREF color);